From df628d4e2191248387ec5397ca23d618320fc726 Mon Sep 17 00:00:00 2001
From: Jeremy Johnson <jeremy.johnson@arm.com>
Date: Tue, 10 Jan 2023 14:40:54 +0000
Subject: Update for RESCALE spec apply_add clarification

Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: I6958904c2c8932e9fe03b3092672d62a06e96ee6
---
 reference_model/src/ops/type_conversion.cc | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/reference_model/src/ops/type_conversion.cc b/reference_model/src/ops/type_conversion.cc
index cb57340..f266675 100644
--- a/reference_model/src/ops/type_conversion.cc
+++ b/reference_model/src/ops/type_conversion.cc
@@ -159,8 +159,15 @@ int OpRescale<Rank, InDtype, OutDtype>::eval()
                         else
                             scaled = TosaReference::QuantUtil::apply_scale_16(input_zp_shifted, channel_multiplier,
                                                                               channel_shift);
-                        scaled               = scaled + output_zp;
-                        OutEigenType out_val = static_cast<OutEigenType>(scaled);
+                        int64_t res_in_64 = static_cast<int64_t>(scaled) + output_zp;
+                        int64_t i32_max_in_64 = static_cast<int64_t>(std::numeric_limits<int32_t>::max());
+                        int64_t i32_min_in_64 = static_cast<int64_t>(std::numeric_limits<int32_t>::min());
+                        if (res_in_64 > i32_max_in_64 || res_in_64 < i32_min_in_64)
+                        {
+                            std::string desc = "scaling result [" + std::to_string(scaled) + "] plus output_zp [" + std::to_string(output_zp) + "] not in i32 range";
+                            throw desc;
+                        }
+                        OutEigenType out_val = static_cast<OutEigenType>(res_in_64);
                         out_val              = std::max<OutEigenType>(out_val, QMin);
                         out_val              = std::min<OutEigenType>(out_val, QMax);
                         return out_val;
@@ -174,7 +181,7 @@ int OpRescale<Rank, InDtype, OutDtype>::eval()
         }
         catch (std::string desc)
         {
-            REQUIRE(false, "OpRescale apply_scale_32/16() fails: %s.", desc.c_str());
+            REQUIRE(false, "OpRescale failure: %s.", desc.c_str());
         }
     }
     else
@@ -193,8 +200,16 @@ int OpRescale<Rank, InDtype, OutDtype>::eval()
                 else
                     scaled =
                         TosaReference::QuantUtil::apply_scale_16(input_zp_shifted, tensor_multiplier, tensor_shift);
-                scaled               = scaled + output_zp;
-                OutEigenType out_val = static_cast<OutEigenType>(scaled);
+                int64_t res_in_64 = static_cast<int64_t>(scaled) + output_zp;
+                int64_t i32_max_in_64 = static_cast<int64_t>(std::numeric_limits<int32_t>::max());
+                int64_t i32_min_in_64 = static_cast<int64_t>(std::numeric_limits<int32_t>::min());
+                if (res_in_64 > i32_max_in_64 || res_in_64 < i32_min_in_64)
+                {
+                    std::string desc = "scaling result [" + std::to_string(scaled) + "] plus output_zp [" + std::to_string(output_zp) + "] not in i32 range";
+                    throw desc;
+                }
+
+                OutEigenType out_val = static_cast<OutEigenType>(res_in_64);
                 out_val              = std::max<OutEigenType>(out_val, QMin);
                 out_val              = std::min<OutEigenType>(out_val, QMax);
                 return out_val;
@@ -202,7 +217,7 @@ int OpRescale<Rank, InDtype, OutDtype>::eval()
         }
         catch (std::string desc)
         {
-            REQUIRE(false, "OpRescale apply_scale_32/16() fails: %s.", desc.c_str());
+            REQUIRE(false, "OpRescale failure: %s.", desc.c_str());
         }
     }
 
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